Does the CDN for Microsoft Windows Update seem to be malfunctioning?

I purchased a code signing certificate, but strangely, Windows did not automatically download the missing root certificate.

When I tried to manually download the root certificate according to the manual, I found that the CDN seemed to return the wrong certificate and I was unable to establish a secure connection with the website. (At least in Chinese Mainland)

https://ctldl.windowsupdate.com/msdownload/update/v3/static/trustedr/en/test/authrootstl.cab

Can other regions be accessed normally?